The Base Rate Fallacy

I walk out the Old Bailey in disgust and go back to Bunhill Fields. Back to Blake, Bunyan, and Bayes.

The police tape is long gone but you can see where their boots pounded the wet lawn to mud. Daffodils the only colour in the place, a promise of summer beneath skeletal trees and tombstones pressure-washed white as bone.

Bayes reckoned probabilities within probabilities. The chance a flower is a daffodil given it blooms in March. The chance a grave is a poet's given a sealed envelope has been laid beside it. The chance a man is innocent given he was convicted.
 
I recognise her uncle, the one she might have run to but did not. I talked to him back when she was still just a missing person. He's sitting right outside the storehouse, not even looking at it. His own private vigil.

I don't buy it. A cemetery groundsman with emotional problems, still living with his mother but her too whacked out on morphine to give an alibi. Too storybook clean. Too perfect a tabloid demon. He told the court he gave her the kiss of life when he found her, DNA and fingerprints, called an ambulance not the police. Clever, said the prosecutor, but would a clever man contrive to find the body somewhere only he and half a dozen others had the key? Nobody asked that.

They are pulling up a grave on block and tackle. If a clever man wanted to hide a body in a graveyard he'd hide it in the turned earth beneath a rebuilt sarcophagus, not in a shed.

Her friend was convinced she'd go to her uncle. Said they'd discussed it.

On average sixty-seven percent of murdered children are killed by family members.